Planar thermal-insulating device, in particular for the human body

ABSTRACT

The invention relates to a planar heat insulating device, in particular, an item of clothing or a cover for the human body, comprising a shell ( 2; 12 ), which is filled with a heat-insulating material ( 3, 13 ). The shell ( 2, 12 ) has at least one outlet ( 32 ) provided, by means of which a reduction of the gas volume in the thermal-insulating device is possible. The insulating power of the thermal-insulating device can thus be varied, in particular reduced, by, for example, a factor of 10, by means of a considerable volume reduction. An item of clothing can thus be produced which may have thermal-insulation properties, optimised to suit the wearers activities with differing levels of physical exertion.

[0001] This invention relates to a sheetlike heat-transfer control article, especially a garment or a blanket for the human body, having a sheath which is filled with a thermally insulating material. Further examples of such heat-transfer control articles are sleeping bags, helmets, medical wound dressings, clothing for motorcyclists or athletes.

[0002] Such articles are known for example from U.S. Pat. No. 5,655,237. It is general prior art, not only in relation to garments but also in relation to blankets, to construct these to have a sheath which forms the outer or inner skin and can be for example water impervious. In this context, it is also known to use breathable sheaths. A blanket or garment will be filled with an insulating material which can be for example down feathers or synthetic materials.

[0003] When appropriate breathable sheaths are used, such garments offer good thermal insulation and are pleasant to lie on or wear. The disadvantage with such garments or blankets is that different temperatures in the sleeping area especially the contrast between summer and winter each require the use of appropriate differently insulating blankets. Frequently, the sheaths and the inner material are separate, so that the inner material itself in turn consists of a sheath and a thermally insulating material. This as it were inner heat-transfer control article is then removable and can be used in double thickness to improve the insulation. In the clothing sector, for example, jackets are available that offer various levels of insulation, or the user wears various garments on top of one another, as required.

[0004] The thermal insulation offered by blankets and also garments is altered by the users depending on the temperature, the relative humidity and the activity of the person in question. Normally, a human being will wear just enough clothing to stop him or her freezing without physical activity. Yet, physical activity can produce about 5 to 7 times more heat than at rest. In other words, to avoid an excessive increase in the rectal temperature, the heat produced has to be got rid of by sweating.

[0005] DE 94 18 527 U discloses a garment of the type mentioned at the beginning, wherein the sheath shall be subjected to an underpressure. This leads to a thinning of the gas in the sheath and to an increase in the thermal insulation.

[0006] It is against this background that it is an object of the present invention to provide an insulating element of the type mentioned at the beginning that offers variable thermal insulation.

[0007] This object is achieved according to the invention when the sheath is provided with an outlet through which the volume of gas in the heat-transfer control article can be reduced.

[0008] The sucking out of gas (generally ambient air) filling the heat-transfer control article reduces the thickness of the heat-transfer control article. In the simplest case, the sheath, internally and externally, can consist for example of air-and water-impervious film, for example PVC, and the filling is a bulkable material.

[0009] Advantageously, the sheaths, internally and externally, are breathable and consist of polyester, PTFE, hydrophilic or microporous PU and the filler is a bulky, advantageously nonhygroscopic, material which is reducible in volume by the action of pressing forces. This filler can be a nonwoven, consist of hollow fibers and/or be realized using down feathers.

[0010] The result, then, is that the thermal insulation is reduced to such an extent that the largest part of the heat can be given off via convection and radiation, so that the user has to correspondingly sweat less and he or she will also feel more comfortable. The degree of thermal insulation is variable over a relatively wide range. The inventive technique of air-filling a cushion makes it possible to vary the degree of thermal insulation over a wide range (1:4). The breathable air-impervious membrane ensures that the moisture will pass through the layers of clothing nonetheless.

[0011] There are specialty applications, for example garments for firefighters, where the two sheath sides, internally and externally, can also be constructed to be different; more particularly, the sheath which faces outwards can be less breathable, so that when the protective suit comes into contact with hot water vapors from the outside these will not pass through the garment. Normally, however, the higher water vapor partial pressure in the filler will ensure that water vapor is transported to the outside through the less breathable layer.

[0012] Advantageously, the throughlet is a valve, especially a one-way valve. The sheath can be subdivided into individual chambers, for example by quilting off.

[0013] The invention will now be more particularly described by way of example with reference to the drawings, where

[0014]FIG. 1 shows part of a corresponding sheetlike element which comprises a preadjustable thermal insulation module and is in the air-filled state,

[0015]FIG. 2 shows the element of FIG. 1 in the evacuated state,

[0016]FIG. 3 shows an element similar to that of FIG. 1, filled with a manufactured fiber material,

[0017]FIG. 4 shows the element of FIG. 3 in the evacuated state, and

[0018]FIG. 5 shows a schematic view of a blanket featuring an electronic control unit for automatic adjustment of the degree of thermal insulation.

[0019]FIG. 1 shows an element having an external sheath 2 and an internal sheath 12, between which down feathers 3 have been installed. Between the loosely installed down feathers 3 are air chambers 4, since the thermally insulating element is in an air-filled state. This state is signified by reference numeral 1. The air-filled state and the combination with the down feathers 3 are responsible for the thermal insulation of the element being high. This high thermal insulation is particularly due to the thermally insulating effect of the down feathers 3 in conjunction with the air regions 4 included between the down feathers 3.

[0020] The sheaths 2 and 12 can be in particular breathable sheaths, for example of polyester, PTFE or hydrophilic or microporous PU. These sheaths 2 and 12 are airtightly joined to each other at their edges. The way they are connected together can be by adhering, welding or some other form of joining. To allow the contents to be cleaned, this joint can be detachable over a predetermined length at one or more locations, for example via a labyrinth seal.

[0021]FIG. 2, then, shows the same element as in FIG. 1 after an apparatus not depicted in this drawing has withdrawn a substantial portion of the air 4 from the region between the sheaths 2 and 12. The same reference numerals refer to the same features in all the figures. It is to be noted that the amount of down filling in the heat-transfer control article has not changed between the states 1 and 11 in FIGS. 1 and 2. In the appreciably thinner element 11, identifiable through the difference in the thicknesses 5 and 15, the number of air pockets 4 and hence the total volume of the air included between the sheaths 2 and 12 has been substantially reduced. This has accordingly likewise reduced the insulating capacity of the insulating element. The applicant company has experimentally determined that the insulating capacity of the insulating element can be reduced up to, for example, a factor of 8 by an appreciable reduction in volume. Other, higher reductions in insulating capacity are possible as well, depending on the settings for the fill level and the degree of evacuation.

[0022] The volume reduction can be effected by letting off air 4 via valve 32. This can be accomplished manually by exerting pressure on the material or by means of a pump. Instead of the air 4 it is also possible to fill some other predetermined gas or gas mixture in between the sheaths 2, 12, which is then not let off into the ambient air but captured in a separate reservoir, for example in a pressure vessel which is fillable by the pump mentioned. The reservoir can be sized, especially oversized, so that it can absorb diffusive and other losses over prolonged periods and provide the heat-transfer control article with a long use life.

[0023]FIGS. 3 and 4 show a further heat-transfer control article in the air-filled state 1 and in the evacuated state 11, the filling of the insulating element being formed in this case by an elongate and sheetlike nonwoven material 13. Here too removal of the air which is situated between the layers 2 and 12 makes it possible to substantially reduce the insulating material in its thickness 15.

[0024] It is a characteristic of the down 3 or of the nonwoven 13 that it is bulky and compressible by externally applied pressure. Reducing the volume occupied by the elements 3 and 13 removes in particular the air chambers which are situated between individual elements 3 and 13 from the space between the layers 2 and 12 and this leads to a reduction in the insulating capacity.

[0025] A corresponding pressure outlet 32 can be a valve which is constructed as an adjustable one-way valve. The user opens it and presses the air out of the heat-transfer control article. This can be accomplished in the case of a blanket by rolling it up, folding or by using one's own body weight to apply a load. In the case of a garment, a jacket for example, this can be accomplished by the action of the user's own hands and arms on the external sheath while the internal sheath is buttressed against the body. The same procedure is possible in the case of clothing elements covering the arms or the legs.

[0026] It is useful for blankets, and bed blankets in particular, to be provided with an additional outlet valve in order that a transverse through-airing of the blanket be achieved; the daily airing of the blanket is then no longer necessary.

[0027] As well as the fillings mentioned and depicted in the drawings, useful fillings further include for example self-relaxing material and/or a loop-formingly knitted or woven spacer fabric.

[0028]FIG. 5 finally shows an illustrative embodiment of the invention, comprising a blanket 28 to which a pump 31 is connected. The blanket 28 possesses in the previously described manner an enveloping top layer 2 and a bottom layer 12, which is not discernible in the figure. The layers 2 and 12 are welded or otherwise sealingly joined together at the edges 22. The blanket 28 has three throughlets 32 which, through hoses 33, lead to a valve block 34. The valve block provides a communication 35 to the aforementioned pump 31, which, depending on the valve position, pumps air into the blanket 28 or withdraws it therefrom, through the hoses 33. A control line 36 is provided for this purpose. The blanket 28 consists of three chambers 41, 42, 43. Any other number of chambers is conceivable as well. These chambers need not be of equal size either, as will be apparent from the description which follows. The advantage of separate chambers 41, 42, 43, between which there are separating seams 44, is that the user can set a different degree of insulation for particular regions of the body. It is therefore clear that this can be separate for example for the foot region, the leg region, the lower part of the trunk and the upper part of the trunk. Given a sufficiently wide blanket for two people, it is also possible to set different insulating levels for the two people through appropriate transverse division of the chambers. In the simplest form of control, pumped-up chambers 41, 42, 43 are taken as a starting point and an appropriate air volume is pumped out via a flow meter or a timer. Filters on the outlets 32 ensure that no fillers (down feathers 3 or nonwoven material 13) can escape from the chambers.

[0029] A particularly comfortable and automatically working embodiment provides a temperature and/or humidity sensor 37 which is connected via control line 38 or wirelessly to the pump 31 and its control instrument. In this case, an appropriate air volume can be automatically withdrawn from the chambers in accordance with the preset calibrating curve in order to adjust the degree of insulation provided by the blanket according to the outdoor temperature, the room temperature, the atmospheric humidity or other parameters.

[0030] It is to be noted that, in the original state featuring good thermal insulation, the sheaths 2 and 12 are in contact with the filling material 3 or 13, so that air pockets are formed between the individual filling elements 3 and 13, but there is no excessively loose distribution of the filling material allowing convection to occur between the sheaths 2 and 12, something which is to be avoided. The insulating effect in the highly air-filled state would then substantially decrease.

[0031] This heat-transfer control article provides in particular a cover which is suitable for allergics and especially impervious to mite feces. When the heat-transfer control article is used as clothing for motorcyclists, it provides additional crash protection in the event of accidents.

[0032] It is possible for active components to be additionally included in a blanket or clothing. These active components can be plant-based additives, vitamins, drugs or else perfume materials. They can be mixed in via the valve 32 and/or the aforementioned reservoir can be used.

[0033] A blanket is advantageously provided with an electronic controller by means of which the air quantity to be removed is determined via a flow meter and/or a thickness meter between the sheaths 2 and 12 and/or a timer. The gas quantity to be removed is predeterminable by means of a temperature sensor and/or a hygrometer. These various sensors are only mentioned by way of example in that any measured value can find use that can be used as characterizing the room climate.

[0034] It is preferable for appropriate calibrating curves to be stored in the electronic controller 31, so that the apparatus is self-regulatingly active. Such a blanket can be altered in its thermal insulation within relatively wide limits by air being removed from or introduced into the space between the sheaths 2 and 12. The control variable used is in particular the temperature and humidity of the bedroom in which the blanket is used.

[0035] A cycle takes as its starting point the complete evacuation of the air from the blanket. In this state, the blanket is between for example 5 and 7 millimeters in thickness and is suitable for an indoor temperature in the summer, for example 28 degrees Celsius. Depending on the weather outdoors, the amount of air blown into the blanket is controlled as a function of the abovementioned parameters, including especially calibrating curves. Especially the filling material, for example down feathers, will then swell up in the process and occupy a larger volume. Given a blanket measuring 1.6 by 2.4 meters, for example, a maximum thickness is achieved when the amount of air introduced is about 0.3 cubic meters. This maximum thickness of about 8 centimeters provides a thermal insulation of 1 m²K/W and is suitable for a room temperature of 13 to 15 degrees Celsius. Depending on his or her warmth requirements, the sleeper will choose and manually set a progressive or degressive or linear curve for the air volume over the parameter.

[0036] Since reliable thickness measurement cannot be carried out for such a blanket, the fill volume is determined via the running time of the pump. A self-actuatedly calibrating function makes it possible to evacuate the blanket at regular intervals, for example twice a week or just once a week, during the (selectable) unused time (during the day, for example) in a defined manner, whereby the blanket is brought from a minimum fill level, for example 0.015 cubic meters of air, to the requisite air volume indicated by the sensors.

[0037] Useful pumps include in particular membrane pumps, which can suck as well as pump. A sensible cycle (deflating and inflating) will take 10 to 15 minutes for the aforementioned 0.3 cubic meters. Electric valves are advantageously provided between the blanket and the pump in order that the suction and pressure side of the pump may be sealed off airtight with regard to the blanket when the pump is not in operation.

[0038] The evacuating operation, as well as a calibrating function, has the function to remove moisture from the blanket. This complete airing can also be accomplished by a repeated cycle of inflating and deflating.

[0039] As well as in blankets, this control system can also be integrated in garments. Here, the simplest case is for the same parameters to be used of the abovementioned room climate (ambient temperature and humidity), which are both parameters which relate to an air volume which, with regard to the user, is on the other side of the “blanket”. Another crucial factor is the degree of physical exertion of the user. The user's physical activity, which determines whether one feels warm or cold, can be manually adjustable as a switch in a few stages from low to medium to high. It is preferable to use measured parameters which relate to the region between the user and the garment and capture the temperature and humidity level of that region. It is also possible to couple the parameters of the two regions (inside and outside the garment). 

What is claimed is:
 1. A sheetlike heat-transfer control article, especially a garment or a blanket for the human body, having a sheath (2; 12) which is filled with a thermally insulating material (3, 13), characterized in that the sheath (2, 12) is provided with at least one outlet (32) through which the volume of gas in the heat-transfer control article can be reduced.
 2. A heat-transfer control article according to claim 1, characterized in that the sheath consists of an inner sheet (12) and an outer sheet (2) which are airtightly joined to each other at the edges and/or in that the sheath is provided or laminated with an outer as a protective layer to protect against mechanical damage.
 3. A heat-transfer control article according to claim 2, characterized in that the airtight connection provided at their edges is a connection which is detachable over a predetermined length at one or more locations.
 4. A heat-transfer control article according to any of claims 1 to 3, characterized in that the sheaths (2, 12) consist of air-and water-impervious film or in that the sheaths (2, 12) are breathable internally and externally and consist of a breathable water-impervious and air-impervious material and/or of a material selected from the group consisting of polyester, PTFE and hydrophilic or microporous PU.
 5. A heat-transfer control article according to any of claims 1 to 4, characterized in that the filling of the thermally insulating material (3, 13) is a bulkable material.
 6. A heat-transfer control article according to any of claims 1 to 5, characterized in that the filling of the thermally insulating material is a nonwoven (13) and/or in that the filling consists of hollow fibers and/or of down feathers (3) and/or that the filling is realized using self-relaxing material and/or loopformingly knitted or woven spacer fabric.
 7. A heat-transfer control article according to any of claims 1 to 6, characterized in that the outlet (32) is a valve.
 8. A heat-transfer control article according to any of claims 1 to 7, characterized in that the sheath (2, 12) is subdivided into individual chambers (41, 42, 43).
 9. A heat-transfer control article according to any of claims 1 to 8, characterized in that there is an electronic controller (31) whereby, via a pump (31), a predetermined gas which is storable in a reservoir and/or ambient air is removable from or blowable into the heat-transfer control article.
 10. A heat-transfer control article according to claim 9, characterized in that the air quantity to be removed is determinable for the electronic controller (31) via a flow meter and/or a thickness meter between the sheaths (2 and 12) and/or a timer, and/or in that the gas quantity to be removed is predeterminable by means of a temperature sensor and/or a hygrometer, and/or in that a calibrating curve is stored in the electronic controller (31) and is self-regulatingly active. 